How can you become infected with giardia?
You may become infected with giardia if you eat food or drink water that is tainted with human or animal waste. In the United States and Canada, you can get giardia by drinking untreated water from wells, streams, rivers, and lakes. This is true even in mountain lakes and streams where the water may seem very pure. The infection can also happen if you swallow contaminated water while you swim.
You can get giardia from someone else through:
- Close contact with someone who is infected.
- Working in day care centers for young children. For example, if you change a diaper and don't wash your hands afterward, anything or anyone you touch could get infected. You could even get the illness yourself if you touch your mouth or eat food that you've touched. Children in day care centers are also more likely to get infected.
- Working or living in nursing homes or other care centers where people may have poor bowel control and poor hygiene.
- Some types of sexual contact, such as anal-oral contact.
Source: http://www.webmd.com